1. Field of the Invention
The present invention relates to a computer system equipped with a write-only optical disc drive and a write-only optical disc drive for use in such a computer system.
2. Description of the Prior Art
In recent years, in response to the increase in data capacity of data used in personal computers, optical discs which have a great deal of storage capacity than floppy discs have been widely used as a portable storage medium for personal computers. In these optical discs, a CD-ROM is the most widely used type of optical disc due to its low cost and ease of manufacturing. For this reason, in resent years, a CD-ROM drive is a standard equipment in most personal computers. In this connection, high speed CD-ROM drives, which can rotate a CD-ROM at 8-times speed or 12-times speed (with respect to the standard 1-times speed), have recently been developed to provide a faster read-out rate (i.e., data transmission rate). These high performance CD-ROM drives can be mass-produced at a low cost, and they are provided in many personal computers.
More recently, with the development of writable optical discs such as CD-R (CD-Recordable) and CD-RW (CD-Rewritable) as storage mediums, personal computers can also be equipped with CD-R drives or CD-RW drives which carry out record and playback of data to and from such new mediums.
However, because these CD-R and CD-RW drives include a circuit and mechanism for writing data in addition to a circuit for reading out data, a circuit configuration thereof becomes complicated, and the complex structure of such drives make them very expensive compared to CD-ROM drives in which only a circuit for reading out data is provided. Consequently, the cost of a personal computer system goes up substantially if the personal computer system is equipped with such a high-cost CD-R drive or CD-RW drive in addition to a or instead of a CD-ROM drive.
Furthermore, the provision of a writable optical disc drive, such as a CD-R drive or CD-RW drive, in addition to the provision of a CD-ROM drive, means that two optical disc playing back systems are provided in the personal computer, thus leading to redundancy and waste.
Moreover, such CD-R drives and CD-RW drives generally read out data at 2-times speed, although disc drives which can write data at 3-times speed or 4-times speed are also developed. However, since in these writable disc drives a data writing function has a priority, it is difficult to achieve the high data transmission rate for reading out data that is possible with the high speed CD-ROM drives described above. Consequently, only for reading out data, that is playing back an optical disc, CD-ROM drives are faster and easier to use than the CD-R and CD-RW drives.